" A system update for Nintendo 3DS is now available and brings with it new features that enable Nintendo Network ID functionality, as well as the ability to browse and post on Miiverse.
The update will allow users to register a Nintendo Network ID to their Nintendo 3DS system. If they also have a Wii Usystem, they can use the same Nintendo Network ID to combine their Nintendo eShop balances and Wish Lists. A Nintendo Network ID is required to download free content, like game demos, from the Nintendo eShop on Nintendo 3DS.
In addition, Miiverse support has been added, allowing Nintendo 3DS users to connect with players around the world to share experiences and game tips. While the full Miiverse experience on Nintendo 3DS requires a broadband Internet connection, there is also an offline mode for players without access to Wi-Fi. Users can queue up to three posts while in this mode, and those posts can be manually posted to Miiverse once a Wi-Fi connection has been established. As with Miiverse on Wii U, users can include select screen shot content from either the top or bottom screen of the Nintendo 3DS system.
The update also lets Nintendo 3DS owners transfer all of their content to different Nintendo 3DS systems an unlimited number of times, once every seven days. Before the update, users could only perform a system-to-system transfer a total of five times.” via a Nintendo Press release